My 1997 f350 7.5l 4x4 runs awful. sometimes very hard to start, and at times will idle pretty good (slight miss at idle all the time), but when i hit 2000 rpm it dies like i turn off the key. Starts right back up, but again will die as soon as i hit 2000 rpm. I will park the truck and a day or two later, it will start and run fine (except for rough idle). I have replaced pretty much everything, computer, coil, distributor, map sensor, idle air control valve, plugs, wires, fuel filter, ignition control module, fuel pressure regulator. Yes I have been shotgunning this problem. I have taken the truck to 5 or 6 mechanics including two ford dealerships and no one can find anything wrong. I'm completely lost as to where to go next.

 

The old school stuff was so much easier to trouble shoot.

 

What do you have for fuel pressure? Sorry to say but you are far from replacing everything...

Are you getting any codes? Why replace the PCM?

 

Fuel pressure is running in the mid 40's on both pumps. The only codes that it has been throwing are that both O2 sensors are bad even though there is only one O2 sensor on the truck. As far as the PCM is concerned, I replaced it out of desperation. After everything else that I have done, in my apparently clouded thinking, I thought that it had to be the computer. Since they are relatively inexpensive, I decided to give it a try.

 

Are you maintaining pressure at mid range and WOT? I am not familiar with that code. It doesn't sound like an eec-IV code. I will consult my manual after Easter dinner here.

It's not a Cali MAF truck is it? Did your replacement PCM have the same catch code?

 

As far as the fuel pressure is concerned, I only checked it at idle, so I don't know what it is doing at other throttle positions. That code is the one that Oreilly's showed me. This is an OBD-I system. It is not a MAF truck but has the MAP sensor instead and the code on the replacement PCM is the same as the one that I removed.

I drove the truck for about 100 miles yesterday without a hitch. The only problems were the rough idle (as usual) and while running my errands I had to start and stop the truck a few times and when I would restart, the starter was really slow, like it was dragging. The battery is a 1 year old Optima and the charging system checks good. Could it be a bad connection at the starter or a bad starter? If a connection issue, could that be causing my other problems.

 

Could be a bad starter. That's not why your motor won't run right though. You may need a little more diagnostic testing. You should check your fuel pressure above idle.

 

Did you gap your new plugs? Just thought I'd ask because that will make it run rough as well.